| Number | Date | Country | Kind |
|---|---|---|---|
| 85 13499 | Sep 1985 | FRX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2331351 | Seeley | Oct 1943 | |
| 2513093 | Hageman | Jun 1950 | |
| 2618336 | Davidson | Nov 1952 | |
| 2902197 | Potdevin et al. | Sep 1959 | |
| 3405582 | Eichenberger | Oct 1968 | |
| 3644932 | Wallace et al. | Feb 1972 | |
| 3794228 | Colwill et al. | Feb 1974 | |
| 4529114 | Casper et al. | Jul 1985 |
| Number | Date | Country |
|---|---|---|
| 2404840 | Aug 1975 | DEX |
| 1022110 | Feb 1953 | FRX |
| 144182 | Nov 1981 | JPX |
| Entry |
|---|
| Document Burster, IBM Technical Disclosure Bulletin, vol. 16, No. 6, pp. 1753, 1754, Nov. 1973. |